THE SIR SUPPLIED DR. WATT WITH 100MG OF 15N RNA. THE AIM OF THIS PRELIMINARY WORK IS TO ESTABLISH METHODS IN ANIMALS THAT WILL LEAD TO THE APPLICATION OF STABLE ISOTOPE TRACERS TO MEASURING RNA METABOLISM IN MAN UNDER CONDITIONS WHERE THERE ARE SIGNIFICANT ALTERATIONS TO TISSUE FUNCTION OR GROWTH. I WILL USE THE 15N LABELLED RNA TO GENERATE FREE BASES FOR INFUSION INTO RATS. THE RATE OF INCORPORATION OF THE BASES INTO RNA WILL BE MEASURED BY CONTINUOUS FLOW ISOTOPE RATIO MASS SPECTROMETRY AND BY GAS CHROMATOGRAPHY MASS SPECTROMETRY (GC-MS). ASSESSMENT OF THE WHOLE BODY METABOLISM OF THE BASES WILL BE MEASURED FROM THE ENRICHMENT DILUTION OF EACH OF THE BASES RELATIVE TO THEIR INFUSION RATE (MEASURED BY GC- MS). IT IS ANTICIPATED THAT VALIDATION OF THE METHODS IN ANIMALS WILL LEAD TO THE APPLICATION OF THE METHODS TO MEASURE MRNA TURNOVER AND PERHAPS SPECIFIC GENE MRNA SEQUENCES. SUCH METHODS SHOULD PROVE POWERFUL IN HELPING US UNDERSTAND THE REGULATION OF PARTICULAR GENES IN VIVO AND THEIR ALTERATION IN DISEASE OR GROWTH.